Antibody-Mediated Targeting of Antigens to Intestinal Aminopeptidase N Elicits Gut IgA Responses in Pigs.

Many pathogens enter the host via the gut, causing disease in animals and humans. A robust intestinal immune response is necessary to protect the host from these gut pathogens. Despite being best suited for eliciting intestinal immunity, oral vaccination remains a challenge due to the gastrointestinal environment, a poor uptake of vaccine antigens by the intestinal epithelium and the tolerogenic environment pervading the gut. To improve uptake, efforts have focused on targeting antigens towards the gut mucosa. An interesting target is aminopeptidase N (APN), a conserved membrane protein present on small intestinal epithelial cells shown to mediate epithelial transcytosis. Here, we aimed to further optimize this oral vaccination strategy in a large animal model. Porcine APN-specific monoclonal antibodies were generated and the most promising candidate in terms of epithelial transcytosis was selected to generate antibody fusion constructs, comprising a murine IgG1 or porcine IgA backbone and a low immunogenic antigen: the F18-fimbriated E. coli tip adhesin FedF. Upon oral delivery of these recombinant antibodies in piglets, both mucosal and systemic immune responses were elicited. The presence of the FedF antigen however appeared to reduce these immune responses. Further analysis showed that F18 fimbriae were able to disrupt the antigen presenting capacity of intestinal antigen presenting cells, implying potential tolerogenic effects of FedF. Altogether, these findings show that targeted delivery of molecules to epithelial aminopeptidase N results in their transcytosis and delivery to the gut immune systems. The results provide a solid foundation for the development of oral subunit vaccines to protect against gut pathogens.

Long-Term Persistence and Relevant Therapeutic Impact of High-Titer Viral-Neutralizing Antibody in a Convalescent COVID-19 Plasma Super-Donor: A Case Report.

A convalescent, non-severe, patient with COVID-19 was enrolled as a hyper-immune plasma voluntary donor by the Immuno-Hematology and Transfusion Unit of the Regina Elena National Cancer Institute in Rome, under the TSUNAMI national study criteria. During a nearly 6-month period (May-October 2020), the patient was closely monitored and underwent four hyperimmune plasma collections. Serum SARS-CoV-2 (anti-S + anti-N) IgG and IgM, anti-S1 IgA, and neutralizing titers (NTs) were measured. Anti-SARS-CoV-2 antibody levels steadily decreased. No correlation was found between anti-S/anti-N IgG and IgM levels and viral NT, measured by either a microneutralization test or the surrogate RBD/ACE2-binding inhibition test. Conversely, NTs directly correlated with anti-S1 IgA levels. Hyperimmune donor plasma, administered to five SARS-CoV-2 patients with persistent, severe COVID-19 symptoms, induced short-term clinical and pathological improvement. Reported data suggest that high NTs can persist longer than expected, thus widening hyperimmune plasma source, availability, and potential use. In vitro RBD/ACE2-binding inhibition test is confirmed as a convenient surrogate index for neutralizing activity and patients' follow-up, suitable for clinical settings where biosafety level 3 facilities are not available. IgA levels may correlate with serum neutralizing activity and represent a further independent index for patient evaluation.

Novel oncolytic adenovirus expressing enhanced cross-hybrid IgGA Fc PD-L1 inhibitor activates multiple immune effector populations leading to enhanced tumor killing in vitro, in vivo and with patient-derived tumor organoids.

BACKGROUND: Despite the success of immune checkpoint inhibitors against PD-L1 in the clinic, only a fraction of patients benefit from such therapy. A theoretical strategy to increase efficacy would be to arm such antibodies with Fc-mediated effector mechanisms. However, these effector mechanisms are inhibited or reduced due to toxicity issues since PD-L1 is not confined to the tumor and also expressed on healthy cells. To increase efficacy while minimizing toxicity, we designed an oncolytic adenovirus that secretes a cross-hybrid Fc-fusion peptide against PD-L1 able to elicit effector mechanisms of an IgG1 and also IgA1 consequently activating neutrophils, a population neglected by IgG1, in order to combine multiple effector mechanisms. METHODS: The cross-hybrid Fc-fusion peptide comprises of an Fc with the constant domains of an IgA1 and IgG1 which is connected to a PD-1 ectodomain via a GGGS linker and was cloned into an oncolytic adenovirus. We demonstrated that the oncolytic adenovirus was able to secrete the cross-hybrid Fc-fusion peptide able to bind to PD-L1 and activate multiple immune components enhancing tumor cytotoxicity in various cancer cell lines, in vivo and ex vivo renal-cell carcinoma patient-derived organoids. RESULTS: Using various techniques to measure cytotoxicity, the cross-hybrid Fc-fusion peptide expressed by the oncolytic adenovirus was shown to activate Fc-effector mechanisms of an IgA1 (neutrophil activation) as well as of an IgG1 (natural killer and complement activation). The activation of multiple effector mechanism simultaneously led to significantly increased tumor killing compared with FDA-approved PD-L1 checkpoint inhibitor (Atezolizumab), IgG1-PDL1 and IgA-PDL1 in various in vitro cell lines, in vivo models and ex vivo renal cell carcinoma organoids. Moreover, in vivo data demonstrated that Ad-Cab did not require CD8+ T cells, unlike conventional checkpoint inhibitors, since it was able to activate other effector populations. CONCLUSION: Arming PD-L1 checkpoint inhibitors with Fc-effector mechanisms of both an IgA1 and an IgG1 can increase efficacy while maintaining safety by limiting expression to the tumor using oncolytic adenovirus. The increase in tumor killing is mostly attributed to the activation of multiple effector populations rather than activating a single effector population leading to significantly higher tumor killing.

Anti-N-methyl-d-aspartate receptor encephalitis in an older patient presenting with a rapid onset of delusions and amnesia.

We present the case of a 77-year-old patient with a rapid onset of delusions, amnesia, agitation, insomnia and no previous psychiatric history, who was diagnosed with anti-N-methyl-d-aspartate receptor encephalitis. This case report highlights the importance of including autoimmune encephalitis in the differential diagnosis of older patients presenting with rapid onset psychiatric episodes.

Oral immunoglobulin for preventing necrotizing enterocolitis in preterm and low birth weight neonates.

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common emergency involving the gastrointestinal tract occurring in the neonatal period. There have been published reports that suggest that oral immunoglobulins (Ig)A and IgG produce an immunoprotective effect in the gastrointestinal mucosa. OBJECTIVES: To determine the effect of oral immunoglobulin on the incidence of necrotizing enterocolitis and other complications in preterm or low birth weight (or both) neonates. SEARCH METHODS: We used the standard search strategy of the Cochrane Neonatal Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2016, Issue 1), PubMed (1966 to January 2016), CINAHL (1982 to January 2016) and EMBASE (1980 to January 2016) and conference proceedings. SELECTION CRITERIA: All randomized or quasi-randomised controlled trials where oral immunoglobulins were used as prophylaxis against NEC in preterm (less than 37 weeks' gestation) or low birth weight (less than 2500 gram), or both, neonates. DATA COLLECTION AND ANALYSIS: We performed data collection and analysis in accordance with the standard methods of the Cochrane Neonatal Review Group. MAIN RESULTS: The search identified five studies on oral immunoglobulin for the prevention of NEC of which three met the inclusion criteria. In this review of the three eligible trials (including 2095 neonates), the oral administration of IgG or an IgG/IgA combination did not result in a significant reduction in the incidence of definite NEC (typical risk ratio (RR) 0.84, 95% confidence interval (CI) 0.57 to 1.25; typical risk difference (RD) -0.01, 95% CI -0.03 to 0.01; 3 studies, 1840 infants), suspected NEC (RR 0.84, 95% CI 0.49 to 1.46; RD -0.01, 95% CI -0.02 to 0.01; 1 study, 1529 infants), need for surgery (typical RR 0.21, 95% CI 0.02 to 1.75; typical RD -0.03, 95% CI -0.06 to 0.00; 2 studies, 311 infants) or death from NEC (typical RR 1.10, 95% CI 0.47 to 2.59; typical RD 0.00, 95% CI -0.01 to 0.01; 3 studies, 1840 infants). AUTHORS' CONCLUSIONS: Based on the available trials, the evidence does not support the administration of oral immunoglobulin for the prevention of NEC. There are no randomized controlled trials of oral IgA alone for the prevention of NEC.

Comparison of prophylactic use of intravenous immunoglobulin versus Pentaglobin® in pediatric patients after hematopoietic stem cell transplantation.

There are few studies evaluating the use of IgM-enriched IVIG (Pentaglobin(®) ) in HSCT recipients. This study aimed to compare the efficacy of prophylactic use of IVIG versus prophylactic use of Pentaglobin(®) within the first 100 days after allogeneic HSCT. We performed a prospective, randomized study of the use of prophylactic IVIG versus prophylactic use of Pentaglobin(®) in patients after allogeneic HSCT. The first dose of IVIG or Pentaglobin(®) was given before conditioning regimen and after transplant was given on day +1, +8, +15, and +22. And then, it was given if IgG level was below 400 mg/dL. Twenty-seven patients in IVIG group and 32 patients in Pentaglobin(®) group were included in the study. There were no significant differences in the duration of neutropenia, hospitalization, fever, and in the number of pyrexial episode, septicemia, bacteremia, local infection, CMV infection, acute GVHD, VOD, and adverse events between the IVIG group and Pentaglobin(®) group. Randomized placebo-controlled trials are needed to conclude that utilization of IVIG or Pentaglobin(®) has no beneficial effect in HSCT.

The protective effects of IgM-enriched immunoglobulin and erythropoietin on the lung and small intestine tissues of rats with induced sepsis: biochemical and histopathological evaluation.

CONTEXT: Sepsis continues to be a significant problem for critical care patients. OBJECTIVE: To evaluate the protective effects of IgM-enriched immunoglobulin and erythropoietin on pulmonary and small intestine tissues in a rat model of intra-abdominal sepsis induced via the cecal ligation and puncture (CLP) method. MATERIALS AND METHODS: Male Sprague-Dawley rats were used. Control group (n = 6): surgical procedure was not performed. Laparotomy was only performed in the sham group (n = 6) and CLP was only performed in the sepsis (CLP) group (n = 30). After erythropoietin (2000 U/kg, intraperitoneal) was given in the sepsis + erythropoietin (CLP + EPO) group (n = 30), IgM-enriched immunoglobulin (600 mg/kg, intraperitoneal) was given in the sepsis + pentaglobin (CLP + PEN) group (n = 30), CLP was created. Intracardiac blood samples were collected for biochemical analysis; lung and small intestine tissue samples were removed for histopathological evaluation. RESULTS: Plasma TNF-α levels (pg/ml) were similar among CLP, CLP + EPO, and CLP + PEN groups (204.0 ± 52.4, 198.5 ± 17.3, and 214.6 ± 93.6, respectively). The CLP group had higher plasma IL-1ß levels (pg/ml) compared with CLP + EPO and CLP + PEN groups (325.1 ± 134.1, 164.3 ± 25.6, and 186.3 ± 26.0, respectively) (p < 0.05). Rats in CLP + EPO and CLP + PEN groups had abolished histopathologic appearance of lung and small intestine tissues compared with rats in the CLP group. DISCUSSION AND CONCLUSION: Our findings support the use of EPO and IgM-enriched immunoglobulin in the prevention of lung and small intestine injuries associated with sepsis.

Perioperative management of an IgA-deficient recipient of a double-lung transplant.

PURPOSE: When exposed in the perioperative period to blood components containing immunoglobulin (Ig)A IgA-sensitized IgA-deficient patients are at an increased risk of transfusion-associated anaphylaxis. We present the case of an IgA-deficient patient whose candidacy for double-lung transplantation was under review in the preoperative period. CLINICAL FEATURES: A 49-yr-old patient with end-stage chronic obstructive lung disease secondary to deficiencies in IgA and IgG subclasses was being assessed for double-lung transplantation. Early recognition of the ramifications of perioperative transfusion prompted consultation with the transfusion medicine service. This in turn facilitated specialized laboratory testing and the coordinated provision of appropriate blood products for the unpredictable date of transplantation. The theoretical systemic risks of a non-IgA-deficient graft on the sensitized IgA-deficient host were considered. To affirm the patient's candidacy for transplantation, he was ultimately challenged preoperatively with IgA-containing products in a controlled intensive-care setting. CONCLUSION: Through a multidisciplinary approach [corrected], a successful transplantation outcome was achieved in an IgA-deficient patient undergoing major surgery. Strategies to mitigate risk include the procurement and transfusion of IgA-deficient components, which may be challenging or untenable in emergent perioperative settings.

Intravenous immunoglobulins prevent the breakdown of the blood-brain barrier in experimentally induced sepsis.

INTERVENTIONS: The effects of immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M on blood-brain barrier integrity and survival rates in septic rats were comparatively investigated. MEASUREMENTS: Sepsis was induced by cecal ligation and perforation in Sprague-Dawley rats. The animals were divided into the following groups: Sham, cecal ligation and perforation, cecal ligation and perforation plus immunoglobulin G (250 mg/kg, intravenous), and cecal ligation and perforation plus immunoglobulins enriched with immunoglobulin A and immunoglobulin M (250 mg/kg, intravenous). Immunoglobulins were administered 5 mins before cecal ligation and perforation and the animals were observed for behavioral changes for 24 hrs following cecal ligation and perforation. Blood-brain barrier permeability was functionally and structurally evaluated by determining the extravasation of Evans Blue and horseradish peroxidase tracers, respectively. Immunohistochemistry and Western blotting for occludin were performed. MAIN RESULTS: The high mortality rate (34%) noted in the septic rats was decreased to 15% and 3% by immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M, respectively (p < .01). Both immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M alleviated the symptoms of sickness behavior in the septic rats, with the animals becoming healthy and active. Increased extravasation of Evans Blue into the brain tissue of the septic rats was markedly decreased with the administration of both immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M (p < .01). Occludin expression remained essentially unchanged in all groups, including the cecal ligation and perforation group. In the cecal ligation and perforation group, increased luminal and abluminal vesicles containing electron-dense horseradish peroxidase-reaction product were noted in the cytoplasm of endothelial cells located in the hippocampus and the cerebral cortex. Tight junction was ultrastructurally intact, suggesting that the transcellular pathway is responsible for the blood-brain barrier breakdown in sepsis. Following immunoglobulin G or immunoglobulins enriched with immunoglobulin A and immunoglobulin M treatment, no ultrastructural evidence of leaky capillaries in the brain was observed in the septic rats, indicating the blockade of the transcellular pathway by immunoglobulins administration. CONCLUSIONS: Our study suggests that immunoglobulin G and immunoglobulins enriched with immunoglobulin A and immunoglobulin M improve the integrity of the blood-brain barrier and inhibits cecal ligation and perforation-induced symptoms of sickness behavior in rats.

Complement-dependent tumor cell lysis triggered by combinations of epidermal growth factor receptor antibodies.

Therapeutic monoclonal antibodies against the epidermal growth factor receptor (EGFR) have advanced the treatment of colon and head and neck cancer, and show great promise for the development of treatments for other solid cancers. Antibodies against EGFR have been shown to act via inhibition of receptor signaling and induction of antibody-dependent cellular cytoxicity. However, complement-dependent cytotoxicity, which is considered one of the most powerful cell killing mechanisms of antibodies, seems inactive for such antibodies. Here, we show a remarkable synergy for EGFR antibodies. Combinations of antibodies against EGFR were identified, which resulted in potent complement activation via the classic pathway and effective lysis of tumor cells. Studies on a large panel of antibodies indicated that the observed synergy is a general mechanism, which can be activated by combining human IgG1 antibodies recognizing different, nonoverlapping epitopes. Our findings show an unexpected quality of therapeutic EGFR antibodies, which may be exploited to develop novel and more effective treatments for solid cancers.

IgMA-enriched immunoglobulin in neutropenic patients with sepsis syndrome and septic shock: a randomized, controlled, multiple-center trial.

OBJECTIVE: To evaluate the effect of intravenous IgMA-enriched immunoglobulin (ivIGMA) therapy on mortality in neutropenic patients with hematologic malignancies and sepsis syndrome or septic shock. DESIGN: Multiple-center, prospective randomized, controlled study. SETTING: Six university hospitals in Germany. PATIENTS: Patients were 211 neutropenic patients with sepsis syndrome or septic shock after chemotherapy for severe hematologic disorders between 1992 and 1999. INTERVENTIONS: Patients received 1300 mL of ivIGMA (7.8 g IgM, 7.8 g IgA, and 49.4 g IgG) infused intravenously within a period of 72 hrs or human albumin according to the same schedule as ivIGMA. MEASUREMENTS AND MAIN RESULTS: All-cause mortality at 28 days, sepsis-related mortality at 28 days, all-cause mortality at 60 days, mortality from septic shock, and mortality from microbiologically proven Gram-negative sepsis and septic shock were recorded. Immunoglobulin had no benefit over human albumin. The 28-day mortality rate was 26.2% and 28.2% in the ivIGMA and control patients, respectively (difference, 2.0% [95% confidence interval, -10.2 to 14.2 percentage points]). Likewise, the 60-day mortality rate did not differ between both arms (29.6% vs. 34.7% in the ivIGMA and control patients, respectively). Mortality rates in patients with sepsis syndrome (17.1% vs. 16.7%) and septic shock (51.9% vs. 54.8%) were also found to be similar between both groups. CONCLUSIONS: Intravenous ivIGMA had no beneficial effects in neutropenic patients with hematologic malignancies and sepsis syndrome and septic shock.

Passive protection with immunoglobulin A antibodies against tuberculous early infection of the lungs.

We report on a new approach toward protection against tuberculosis, based on passive inoculation with immunoglobulin A (IgA) antibodies. In a mouse model of tuberculous lung infection, intranasal inoculations of mice with an IgA monoclonal antibody (mAb) against the alpha-crystallin antigen of Mycobacterium tuberculosis reduced up to 10-fold the lung bacterial counts at nine days after either aerosol- or intranasal challenge. This effect involved synergism between mAb inoculations shortly before and 3 days after infection. Monomeric IgA reduced the colony-forming unit counts to the same extent as the polymeric IgA, suggesting antibody targeting to Fcalpha, rather than poly-immunoglobulin receptors on infected lung macrophages. The protective effect was of short duration, presumably due to the rapid degradation of the intranasally applied IgA. Our results provide evidence of an alternative approach which could be further developed toward immunoprophylaxis against tuberculosis in immunocompromised subjects.

Oral immunoglobulin for preventing necrotizing enterocolitis in preterm and low birth-weight neonates.

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common emergency of the gastrointestinal tract occurring in the neonatal period. There have been published reports which suggest that oral immunoglobulins IgA and IgG produce an immunoprotective effect in the gastrointestinal mucosa. This systematic review was undertaken to clarify the issue. OBJECTIVES: To assess whether oral immunoglobulin administered to preterm and low birth-weight neonates reduces the incidence of necrotizing enterocolitis without adverse effects. SEARCH STRATEGY: The databases MEDLINE, CINAHL, EMBASE (1966 to October 26, 2003) and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2003) were searched. Proceedings of the Perinatal Society of Australia and New Zealand were hand searched. The computer neonatal discussion site 'Nicu Net' was also used. Additionally, all references in the identified trials were checked and authors were contacted to request any additional published or unpublished data. No new trials were identified. SELECTION CRITERIA: All randomised or quasi-randomised controlled trials where oral immunoglobulins were used as prophylaxis against necrotizing enterocolitis in preterm (<37 weeks gestation) and/or low birth-weight (<2500 gms) neonates. DATA COLLECTION AND ANALYSIS: The procedures of the Cochrane Neonatal Review Group (CNRG) were used. The two reviewers independently assessed the trials for their methodological quality and subsequent inclusion in the review. Relative risk (RR), risk difference (RD), and number needed to treat (NNT) were used in the analysis. MAIN RESULTS: Five studies on oral immunoglobulin for the prevention of necrotizing enterocolitis were identified of which three met the inclusion criteria. In this review of the three eligible trials (including a total of 2095 neonates) the oral administration of IgG or an IgG/IgA combination did not result in a significant reduction in the incidence of definite NEC [RR 0.84 (95% CI 0.57, 1.25), RD -0.01 (95% CI -0.03, 0.01)], suspected NEC [RR 0.84 (95% CI 0.49, 1.46), RD -0.01 (95% CI -0.02, 0.01)], need for surgery [RR 0.21 (95% CI 0.02, 1.75), RD -0.03 (95% CI -0.06, 0.00)] or death from NEC [RR 1.10 (95% CI 0.47, 2.59), RD 0.00 (95% CI -0.01, 0.01)]. REVIEWER'S CONCLUSIONS: Based on the available trials, the evidence does not support the administration of oral immunoglobulin for the prevention of NEC. There are no randomised controlled trials of oral IgA alone for the prevention of NEC.

[Unrelated donor stem cell transplantation in children: low toxicity using a GvHD-prophylaxis regimen with CSA, MTX, metronidazole,iv-immunoglobulin and ATG]. / Hämatopoetische Stammzelltransplantation vom Fremdspender bei Kindern: Niedrige Toxizität durch GvHD-Prophylaxe mit CSA, MTX, Metronidazol, iv-Immunglobulin und ATG.

BACKGROUND: Unrelated donor (UD) hematopoietic stem cell transplantation (HSCT) is accepted as a therapy for leukaemic diseases and varying inborn diseases if a suitable related donor cannot be found. The goal of immunosuppressive therapy with UD-HSCT is an effective prevention of graft-versus-host-disease (GvHD) on one hand. On the other hand an optimal balance with immunocompetence of the transplanted bone marrow is desirable in order to prevent graft failure, infection and, in the case of leukaemic diseases, potentially control the underlying disease. PATIENTS AND METHODS: Between 1992 and 2000 49 patients aged 11 months to 16.7 years received an UD-HSCT in Hamburg. Underlying diseases were leukaemia or MDS in 35, of these ALL in 21, hemophagocytic lymphohistiocytosis (HLH) in 9, immunodeficiency or inborn error of metabolism in 5 patients. GvHD-prophylaxis consisted of a combination of Cyclosporin A (CSA), methotrexate (MTX), metronidazole, IgM-enriched iv-immunoglobulin (ivIg) (Pentaglobin(R)) or ivIgG and anti-thymocyte-globulin (ATG). Within the same time span 10 patients with ALL received a matched related donor HSCT (MRD-HSCT). GvHD-prophylaxis in these patients was done without ATG in 8 of 10 cases. UD-HSCT were analyzed for survival, relapse and toxicity. Probability of survival of the patients with ALL after UD-HSCT was compared with results of MRD-HSCT in children with ALL. RESULTS: The Kaplan-Meier estimates of three year overall-survival (OS) were 74 % for all patients. Probability of disease-free survival (DFS) at three years was 62 % for leukaemia/MDS-patients and 100 % for the HLH-patients. Acute GvHD (aGvHD) grades II or III occurred in 51 % of patients. Chronic GvHD (cGvHD) occurred in 22 % of patients. There were 5 cases of treatment-related mortality (TRM). Probability of DFS for patients with ALL at three years was 65 % after UD-HSCT and 30 % in the patients after MRD-HSCT. CONCLUSIONS: UD-HSCT in children is an effective and safe therapy. A GvHD-prophylaxis regimen combining the standard immunosuppressive agents CSA and MTX with ivIg, metronidazole and serotherapy using ATG may result in a low incidence of severe GvHD-complications and low TRM rate without increase in relapse rates.

Oral immunoglobulin for preventing necrotizing enterocolitis in preterm and low birth-weight neonates.

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common emergency of the gastrointestinal tract occurring in the neonatal period. There have been published reports which suggest that oral immunoglobulins IgA and IgG produce an immunoprotective effect in the gastrointestinal mucosa. This systematic review was undertaken to clarify the issue. OBJECTIVES: To assess whether oral immunoglobulin administered to preterm and low birth-weight neonates reduces the incidence of necrotizing enterocolitis without adverse effects. SEARCH STRATEGY: The databases MEDLINE, CINAHL, Embase and the Cochrane Controlled Trials Register were searched. The text words 'necrotising enterocolitis OR necrotizing enterocolitis' AND 'immunoglobulin' with constraints 'neonate OR infant' were used. Proceedings of the Perinatal Society of Australia and New Zealand were hand searched. The computer neonatal discussion site 'Nicu Net' was also used. Additionally, all references in the identified trials were checked and authors were contacted to request any additional published or unpublished data. SELECTION CRITERIA: All randomized or quasi-randomized controlled trials where oral immunoglobulins were used as prophylaxis against necrotizing enterocolitis in preterm (<37 weeks gestation) and/or low birth-weight (<2500 gms) neonates. DATA COLLECTION AND ANALYSIS: The procedures of the Cochrane Neonatal Review Group (CNRG) were used. The two reviewers independently assessed the trials for their methodological quality and subsequent inclusion in the review. Relative risk (RR), risk difference (RD), and number needed to treat (NNT) were used in the analysis. MAIN RESULTS: Five studies on oral immunoglobulin for the prevention of necrotizing enterocolitis were identified of which three met the inclusion criteria. In this review of the three eligible trials (including a total of 2095 neonates) the oral administration of IgG or an IgG/IgA combination did not result in a significant reduction in the incidence of definite NEC [RR 0.84 (95% CI 0.57, 1.25), RD -0.01 (95% CI -0.03, 0.01)], suspected NEC [RR 0.69 (95% CI 0.42, 1.13), RD -0.01 (95% CI -0.03, 0.00)], need for surgery [RR 0.21 (95% CI 0.02, 1.75), RD -0.03 (95% CI -0.06, 0.00)] or death from NEC [RR 1.10 (95% CI 0.47, 2.59), RD 0.00 (95% CI -0.01, 0.01)]. REVIEWER'S CONCLUSIONS: Based on the available trials, the evidence does not support the administration of oral immunoglobulin for the prevention of NEC. There are no randomised controlled trials of oral IgA alone for the prevention of NEC.

IgA antibodies for cancer therapy.

Antibody-based therapy is a new treatment option for selected tumor patients. Today, human IgG(1) is the most widely used isotype, because it effectively activates human complement, recruits NK cells for ADCC, and has an extended plasma half life. In recent work, however, neutrophils--the most populous cytotoxic cells in humans--were more effectively recruited by human IgA than by IgG antibodies. IgA antibodies may have the additional advantages of forming natural dimers with improved signaling capacity on tumor cells, and being actively transported into mucosal secretions with the potential for improved targeting of certain carcinomas from the luminal surface.

Transmission of IgA and IgG monoclonal antibodies to mucosal fluids following intranasal or parenteral delivery.

BACKGROUND: The efficacy by which passive antibodies can reach the lungs could be important for the outcome of immunotherapy of respiratory pulmonary infections. We examined how transmission to a number of mucosal sites is affected by the route of inoculation. METHODS: Transmission of newly raised IgA class Mabs against mycobacterial surface antigens to saliva, lung or vaginal lavage, bile and serum of BALB/c mice was compared with existing IgG Mabs. ELISA was used for testing body fluids obtained 1-24 h after intranasal or intravenous inoculation and 1-7 days following back-pack tumour growth of hybridomas. RESULTS: Intranasal inoculation resulted in a rapid rise and high levels of both IgA and IgG class Mabs in lung lavage. In contrast, following intravenous Mab injection or back-pack tumour growth of hybridoma cells, effective lung transmission was observed for the IgG1 and IgG2b MAbs, but not for the IgA Mabs. The secretory component was acquired by the transmitted IgA MAbs in the mucosal fluids, but not in the serum. Nevertheless, the time course of mucosal IgA antibody levels was similar to that of the tested IgG Mabs. Furthermore, the relative proportion of transmission to saliva and bile varied between individual Mabs indicating a role of tissue-specific, immunoglobulin class-unrelated mechanisms. CONCLUSIONS: Intranasal, rather than parenteral inoculation of mice is required for the efficient delivery of IgA antibodies against respiratory pulmonary pathogens. Interestingly, IgA-secretory component complexing of intranasally applied Mabs did not significantly influence their persistence in the lungs.

Passive IgA monoclonal antibody is no more effective than IgG at protecting mice from mucosal challenge with respiratory syncytial virus.

Respiratory syncytial virus (RSV) is a mucosally restricted pathogen that can cause severe respiratory disease. Although parenteral administration of sufficient RSV-specific IgG can reduce severity of lower respiratory tract infection in high-risk infants, delivery of antibody by direct airway administration is an attractive alternative. Topical and parenteral administration of an IgA monoclonal antibody (MAb) specific for the RSV F glycoprotein was compared with an IgG MAb, specific for the same antigenic site, for ability to protect mice against RSV infection. Administration of RSV-specific IgG was more effective in reducing RSV titers in lung (4.6 log10 pfu/g) than IgA MAb (3.6 log10 pfu/g) when given intranasally immediately prior to infection (P=.005). RSV titers in the nose were reduced only by prophylactic administration of IgG parenterally. Therefore, topical administration of IgA is no more effective than topically administered IgG and is less effective than systemically administered IgG for protecting against RSV infection.